Conventionally, as the method for bonding together glass sheets there is known a bonding method comprising sandwiching a metal sheet band between the glass sheets and heating the metal sheet band to effect bonding, such bonding methods being disclosed, for example, in U.S. Pat. Nos. 2,920,785 and 3,519,409. In these bonding methods, however, both nonconductive members desired to be mutually bonded are heated to the same high temperature. However, difficulties are presented in bonding where one of the nonconductive members can be damaged by a temperature as high as the bonding temperature.
Further, where a glass member and a metal member are bonded together, a method is well known which comprises heating the metal member utilizing a high frequency current, and locally melting by the resulting heat those portions of the glass member which are desired to be bonded to the metal. For example, in the sealing of an early model of a tubular fluorescent lamp, a metal cap is fitted against an end face of a tubular glass bulb, the cap having a thermal expansion coefficient approximate to that of the glass, and is heated up to a temperature of more than 1000.degree. C using a high frequency induction-heater. The glass bulb end portion is locally melted by the resulting heat to be fused to the cap, and is cooled to complete the glass bonding. This bonding method is indeed simple but requires a high temperature for a long time to achieve the bonding, so that where bonding is carried out in the atmosphere a great deal of, cap oxidation takes place. In addition, a large amount of power is required. Difficulties are also presented in recovering and reusing the glass tube, cap, etc. since it is difficult to dismember the bonded structure.
Further, it has been conventionally regarded as impossible to attach a laser mirror to a plasma tube for use in a laser device by fusing the reflective surface of the laser mirror directly to the plasma tube. This is because the deposited surface of the laser mirror is not resistive to high temperature, the mirror substrate may be deformed. For these reasons, said attachment has been accomplished by using an organic bonding agent such as epoxy resin or the like, or where the sealing is conducted using a molten glass, the method of, for example, fitting a metal piece such as Kovar to the peripheral portion of the rear face of the mirror has been customarily carried out. But in the case where the organic bonding agent is used, the bonding life could be expected to have only a length of 1000 to 2000 hours at most, while in the case where molten glass is employed, the resulting sealed structure became complicated in construction, expensive and heavy. As a result the laser tube is likely to be distorted, and the laser device has its functional stability lowered.